What can cause a "failure to thrive" in children?

The term "failure to thrive" refers to a condition in which a child does not gain weight or grow appropriately compared to established growth standards for their age and gender. This can stem from a variety of underlying issues, including inadequate caloric intake, malabsorption, or other health problems. Option C accurately describes a scenario where a child's weight gain or current weight falls below the expected norms for their gender and age, making it a clear indicator of failure to thrive. It signifies that the child's growth is not meeting the developmental milestones, which are crucial for healthy physical and cognitive development.

In contrast, excessive weight gain would not denote failure to thrive but rather an issue with overnutrition. Achieving a normal weight for age signifies adequate growth and does not indicate a problem. Rapid weight loss could be a concerning sign, but it doesn't encompass the broader spectrum of indicators associated with failure to thrive, which focuses on consistent underperformance in weight gain relative to peers.